1. Field of the Invention
The present invention relates to a technology for processing image data to be written by a write control device.
2. Description of the Related Art
In an image forming apparatus based on electrophotography, a photosensitive element is scanned with a light beam to write a latent image on the photosensitive element. The latent image formed on the photosensitive element is sometimes skewed because a running axis of the photosensitive element does not make a right angle with an optical axis of the light beam. Sometimes the latent image is distorted because of a distortion of the optical axis.
To perform correction on such a writing characteristic, for example, Japanese Patent Application Laid-open No. H03-142412 discloses an image forming apparatus in which the optical axis is physically shifted by using a motor. However, this technique requires additional costs for the motor.
Japanese Patent Application Laid-open No. 2007-88928 discloses an image forming apparatus by which the correction on the image can be performed with lower costs. Specifically, the image forming apparatus includes line buffers for storing data corresponding to a plurality of lines of the image therein. When image data is read from the line buffers before the image data is written by an image processing operation, the image data is shifted in the sub-scanning direction to correct distortion of the image.
However, in the technology disclosed in Japanese Patent Application Laid-open No. 2007-88928, a correction amount of the image is limited to the number of the lines for which the line buffers are provided, and a built-in buffer (built-in memory) included in the image forming apparatus is expensive. Furthermore, because the number of the lines is determined when the image forming apparatus is designed, the number of the lines cannot be dynamically changed.